1. Field of the Invention
The present invention relates to a machine tool where the machine body is surrounded by a cover. The machine body comprises a tool post disposed on a fixed bed on one side thereof nearer to an operator, and a headstock provided on the other side of the fixed bed farther from the operator on which a workpiece is to be mounted thereon.
2. Discussion of the Related Art
Conventionally a mass-production type machine tool (such as a Numerically Controlled lathe also called an NC lathe) has carriages with a tool post mounted on each carriage are provided on the left and right sides of the front side (nearer side to the operator) of the fixed bed. A headstock is provided on the rear side (the side farther from the operator) between the two tool posts. In each of the tool posts, a turret head with a plurality of tools mounted thereon is provided on a tool post body so as to be rotationally indexable. In this arrangement, a workpiece mounted on the headstock is worked and shaped by moving the tool posts and the carriage relative to each other.
Also, in this machine tool, it has been conventional to have the machine body surrounded by a cover in order to prevent chips and coolant from scattering outside of the machine. In this arrangement, a wide operational opening is formed in a front wall located on the operator side of the cover so that the operational opening is opened and closed by a door.
With this conventional machine tool, since its structure has the headstock disposed on the rear side of the left-and-right tool posts, the turret head is provided on the headstock side of the tool post body, i.e., on the rear side of the tool post body. As a result of this structure, replacing a tool set on the turret head requires the operator to carry out the tool loading and unloading operation in a manner that brings his or her hands around from the operational opening formed in the front wall to the rear side of the tool post body. In this machine tool, the tool post body interferes with the replacement work, resulting in a difficult replacement with poor workability.